Add CONTRIBUTING and LICENSE files

[galennare]

Repo is missing "contributing" documentation which makes it confusing for new people who want to add new features or help with the project's TODO list. Also could help maintainers set standards for PRs and Issues as well as templates for people who are working off of a forked repo.

Right now the repo has no License file, which implies it falls under All Rights Reserved. This can be problematic for people who are worried about litigation against them in the future if they are to use this for their own ROM hack or even contribute to the project itself. This is especially important since it seems like this project is attempting to maintain a clean-room approach and is using as little content that would be considered owned by Nintendo as possible, so most of it is the IP of whoever originally wrote it.

[BluRosie]

may do a contributing document for sure

code won't get a license though because it's inherently not our code, we just modify it. even if it were fully clean-room decompilation, we additionally have assets like i.e. sprites that wouldn't fall under our assets no matter how we spin it. most of the code is also reliant on data structures that aren't ours as well
the faq mentions that we ask that folks do not force hack players to pay for any access to their hack to deter financial gain, but otherwise the choice to not license is intentional